1. Field of the Invention
The present invention relates to touch panels having press detection function.
2. Background Art
Conventionally, note PCs having a touch pad have been known. Such note PCs are provided with UI having good usability, i.e., when moving a cursor, it is possible to freely operate the cursor on the display by just tracing the operation surface of the note PC with a finger.
Furthermore, recently, electronic devices having a touch panel such as cellar phones, smart phones, and game machines have been popular. Such electronic devices have a structure of a transparent touch panel provided on a display panel such as LCD, so that it is possible to perform the operation by just touching buttons displayed on the display panel with a finger or a stylus. Furthermore, it is possible to input characters and draw diagrams with a handwriting input. Accordingly, the previously mentioned electronic devices employs UI with which the intuitive input is possible.
However, according to the touch panel, it is impossible to detect the applied load. Accordingly, it is impossible to detect letter description such as brush writing or pushing action, which means that it is insufficient as UI.
On the other hand, piezoelectric sensors have been known which can detect the applied load. For example, according to Japanese Patent Publication 2004-125571, a transparent piezoelectric sensor is disclosed which includes a transparent pressure sensitive layer and a transparent conductive layer.